Writing instrument



FIG. 1 is a perspective view of a writing instrument showing my design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a right view thereof;

FIG. 5 is a left view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines show portions of the writing instrument that form no part of the claimed design. 

CLAIM We claim the ornamental design for a writing instrument, as shown and described. 